以下是的一些我们精选的视频加音乐：iOS 视频添加音乐 去除原声

如果是预览视频，添加音乐这个很简单，使用 AVAudioPlayer 来播放音乐，目前我所做的是播放导入在工程本地的音乐文件，在线网络音乐添加尚未涉及。视频播放使用 AVplayer。 下面是切换背景音乐的方法：

- ( void ) anotherMusic: ( NSURL * ) url withVolume: ( CGFloat ) volume{ _usingMusic = YES; _musicUrl = url; _musicPlayer = [ [ AVAudioPlayer alloc ] initWithContentsOfURL:url error:nil ] ; [ _musicPlayer setVolume:volume ] ; [ _musicPlayer prepareToPlay ] ; [ _musicPlayer play ] ;}

我的功能基本是仿照微博发布视频做的，也有声音大小控制。一行代码控制，超级简单。

- ( void ) changeMusic: ( CGFloat ) value{ [ _musicPlayer setVolume:value ] ; _musicVolume = value;}

如果要关闭背景音乐，调用 AVAudioPlayer 的 stop 方法就行。 如果要控制原声：（想要静音直接将声音的值设为 0）

AVURLAsset *asset = [ AVURLAsset URLAssetWithURL:_videoUrl options:nil ] ; NSArray *audioTracks = [ asset tracksWithMediaType:AVMediaTypeAudio ] ; if ( audioTracks.count>0 ) { AVAssetTrack *assetAudioTrack = audioTracks.firstObject; audioTrack = assetAudioTrack; AVMutableAudioMixInputParameters* audioInputParams = [ AVMutableAudioMixInputParameters audioMixInputParameters ] ; [ audioInputParams setVolume:value atTime:kCMTimeZero ] ; [ audioInputParams setTrackID: [ assetAudioTrack trackID ] ] ; NSArray* audioParams = [ NSArray arrayWithObject:audioInputParams ] ; AVMutableAudioMix* audioMix = [ AVMutableAudioMix audioMix ] ; [ audioMix setInputParameters:audioParams ] ; [ self.playItem setAudioMix:audioMix ] ;

上面都只是预览时可见的效果，这个时候并没有真正的将你要的背景音乐加到视频中去。我们获取视频的 videoTrack 和 audioTrack 进行相应地处理合成再导出，这样才算真正的控制了视频的一切。视频原声的控制（包括音量大小或者直接静音我是写在一个方法中，方便我控制，你也可以写两个方法，静音时不加入 audioTrack，但我觉得两个方法麻烦，一个方法简单点）

- ( void ) removeAudioTrack: ( AVAsset* ) asset{ self.mutableComposition = [ AVMutableComposition composition ] ; AVMutableCompositionTrack *compositionVideoTrack = [ self.mutableComposition addMutableTrackWithMediaType:AVMediaTypeVideo preferredTrackID:kCMPersistentTrackID_Invalid ] ; AVAssetTrack *videoTrack = nil; AVAssetTrack *assetAudioTrack = nil; if ( [ asset tracksWithMediaType:AVMediaTypeVideo ] .count!=0 ) { videoTrack = [ [ asset tracksWithMediaType:AVMediaTypeVideo ] objectAtIndex:0 ] ; } CMTimeRange timeRange = CMTimeRangeMake ( kCMTimeZero, videoTrack.timeRange.duration ) ; if ( videoTrack!=nil ) { [ compositionVideoTrack insertTimeRange:timeRange ofTrack:videoTrack atTime:kCMTimeZero error:nil ] ; } // 测试改变原声 if ( [ [ asset tracksWithMediaType:AVMediaTypeAudio ] count ] != 0 ) { assetAudioTrack = [ asset tracksWithMediaType:AVMediaTypeAudio ] [ 0 ] ; } if ( assetAudioTrack != nil ) { AVMutableCompositionTrack *compositionAudioTrack = [ self.mutableComposition addMutableTrackWithMediaType:AVMediaTypeAudio preferredTrackID:kCMPersistentTrackID_Invalid ] ; [ compositionAudioTrack insertTimeRange:CMTimeRangeMake ( kCMTimeZero, assetAudioTrack.timeRange.duration ) ofTrack:assetAudioTrack atTime:kCMTimeZero error:nil ] ; AVMutableAudioMixInputParameters *mixParameters = [ AVMutableAudioMixInputParameters audioMixInputParametersWithTrack:compositionAudioTrack ] ; [ mixParameters setVolumeRampFromStartVolume:_sound toEndVolume:_sound timeRange:CMTimeRangeMake ( kCMTimeZero,assetAudioTrack.timeRange.duration ) ] ; self.mutableAudioMix = [ AVMutableAudioMix audioMix ] ; self.mutableAudioMix.inputParameters = @ [ mixParameters ] ; }// 导出 self.exportSession = [ [ AVAssetExportSession alloc ] initWithAsset: [ self.mutableComposition copy ] presetName:AVAssetExportPreset1280x720 ] ;// } self.exportSession.videoComposition = self.mutableVideoComposition; self.exportSession.audioMix = self.mutableAudioMix;self.exportSession.outputURL = [ NSURL fileURLWithPath:outputURL ] ;self.exportSession.outputFileType=AVFileTypeQuickTimeMovie; self.exportSession.shouldOptimizeForNetworkUse = YES; [ self.exportSession exportAsynchronouslyWithCompletionHandler:^ ( void ) {switch ( self.exportSession.status ) { case AVAssetExportSessionStatusCompleted:{ dispatch_async ( dispatch_get_global_queue ( DISPATCH_QUEUE_PRIORITY_BACKGROUND, 0 ) , ^{ [ self writeVideoToPhotoLibrary: [ NSURL fileURLWithPath:outputURL ] ] ; } ) ;// Step 3// Notify AVSEViewController about export completion [ [ NSNotificationCenter defaultCenter ] postNotificationName:AVSEExportCommandCompletionNotification object:self ] ; }break;case AVAssetExportSessionStatusFailed:NSLog ( @" 导出失败：Failed:%@",self.exportSession.error ) ;break;case AVAssetExportSessionStatusCancelled:NSLog ( @" 导出取消：Canceled:%@",self.exportSession.error ) ;break;default:break;}} ] ;

添加本地音乐，传入 url。

- ( void ) addMusic: ( AVAsset* ) asset{ CMTimeRange timeRange = CMTimeRangeMake ( kCMTimeZero, [ asset duration ] ) ; AVMutableCompositionTrack *customAudioTrack = [ self.mutableComposition addMutableTrackWithMediaType:AVMediaTypeAudio preferredTrackID:kCMPersistentTrackID_Invalid ] ; AVAssetTrack *assetAudioTrack = nil; if ( [ [ asset tracksWithMediaType:AVMediaTypeAudio ] count ] != 0 ) { assetAudioTrack = [ asset tracksWithMediaType:AVMediaTypeAudio ] [ 0 ] ; } AVAsset *audioAsset = [ [ AVURLAsset alloc ] initWithURL:_musicUrl options:nil ] ; AVAssetTrack *newAudioTrack = [ audioAsset tracksWithMediaType:AVMediaTypeAudio ] [ 0 ] ; [ customAudioTrack insertTimeRange:timeRange ofTrack:newAudioTrack atTime:kCMTimeZero error:nil ] ; AVMutableAudioMixInputParameters *mixParameters = [ AVMutableAudioMixInputParameters audioMixInputParametersWithTrack:customAudioTrack ] ; [ mixParameters setVolumeRampFromStartVolume:_music toEndVolume:_music timeRange:CMTimeRangeMake ( kCMTimeZero,asset.duration ) ] ; NSMutableArray *mut = [ NSMutableArray arrayWithArray:self.mutableAudioMix.inputParameters ] ; [ mut addObject:mixParameters ] ; self.mutableAudioMix.inputParameters = mut;

对了，上面代码还有一个需要注意的地方，如果你只调用 addMusic 方法，记得 self.mutableAudioMix = [ AVMutableAudioMix audioMix ] ; 我上面的代码是音乐先调用了 removeAudioTrack 方法，self,mutableAudioMix 被初始化过了，后面就不用再初始化了。

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